Figure 4.

The induction of miR-221/222 expression is associated with S phase entry of the cell cycle. (A) MTT assays on MDA-MB-231 cells showing cell proliferation inhibition by both anti-miR-221 and anti-miR-222 after 48 h treatment. (B) Northern blot analysis on miR-221/222 expression in MEF cells at different stages of the cell cycle. tRNA served as RNA loading control; western blot analysis of cyclin D1 expression. β-actin served as protein loading control. (C) Cell cycle analysis demonstrated that serum-starved cells were arrested at G₀/G₁ phase (0h timepoint). G₁/S transition occurred at 12 h timepoint after adding 10% FBS back. Values are equal to mean ± SEM (n = 4). * p < 0.05, ** p < 0.01